The invention relates to an improved process for the preparation of 1,1,1-trifluoro-2-aminoalkanes which comprises hydrogenating the corresponding oximes.
1,1,1-trifluoro-2-aminoalkanes are useful as intermediates for the preparation of a variety of compounds which are useful as agrochemicals, pharmaceuticals or dyes. In particular, they are key intermediates in the preparation of insecticidal benzamides as disclosed for example by DE 36 11 193 and of fungicidal 7-(1,1,1-trifluoroalk-2-ylamino)-6-(halophenyl)-triazolopyrimidines which are described for example in PCT/US98/05615.
J. B. Dickey et al., Ind. Eng. Chem. 98, 1956, 209-213 disclose a method for the preparation of 1,1,1 -trifluoro-2-aminopropane by the hydrogenation of the corresponding oxime in a rocking autoclave at a pressure of 150 bar (2.000 p.s.i.) in the presence of Raney Nickel using ether as diluent. However, only 30% of the desired product are obtainable according to this method.
Therefore, the method known from the art is not applicable for large scale production, due to its low yields.